1. Field of the Invention
The present invention relates to stabilizing devices for minimizing sway of a trailer relative to a towing vehicle.
2. Description of the Prior Art
The dangers attendant uncontrolled sway of a towed trailer relative to a towing vehicle have long been known. In effort to minimize these dangers, numerous different sway control devices have been proposed. Examples of these sway control devices include those incorporating a circular friction pad mounted on the frame of a trailer acting on a circular post to controllably resist rotation of a lever arm having its free end coupled to the towing hitch. An example of such a device is shown in U.S. Pat. No. 3,273,911 to Waldie. Such devices, while acceptable for their intended purpose, suffer the shortcoming that wear on the friction pad may result in a deterioration in the effectiveness of the sway control resulting in a dangerous condition. This condition may be exacerbated by the false security stemming from the driver's belief that the sway control is operating effectively.
Other efforts to provide reliable sway control have led to the proposal of a flexible cable or belt fitted over a friction shoe mounted on the towing vehicle and having the opposite ends thereof secured to the opposite sides of the trailer frame. A device of this type is shown in U.S. Pat. No. 4,052,085 to Rendessy. Such a device is relatively cumbersome to install and renders fine adjustment thereof relatively difficult and may exhibit shortcomings in reliability.
Other efforts have led to a proposal that friction bars be mounted from the towing vehicles on opposite sides of the trailer frame and telescoped through a friction adjustment arrangement providing for screwing of a bolt in a threaded bore to vary the application of frictional force applied to the respective bars. Such a device, while satisfactory for the intended use, does suffer the shortcoming that the restrictive frictional forces applied to the bars results in application of forces out of alignment with one another, thereby resulting in uneven application of restrictive forces and consequent irregular operation and uneven wear. A device of this type is shown in U.S. Pat. No. 3,552,771 to Hendricks.
In other sway control devices, different adjustment screw arrangements have been proposed for making an adjustment to accommodate for worn friction or brake pads in sway control devices, such adjustments have proven to be relatively unpredictable in maintaining the desired control in the amount of resistance presented to sway of the trailer relative to the vehicle. One difficulty encountered is the fact that friction pads oftentimes wear irregularly across the friction surfaces thereof, thus resulting in an uneven application of resistive forces upon subsequent operation thereof. In other arrangements, the forward and rearward attachment points are unsymmetrical about the longitudinal center line resulting in unequal distribution of forces leading to racking of the device upon operation thereof.
Consequently, there exists a need for a sway control device which will provide for relatively even wear of the friction pads across the surface thereof and an adjustment device to allow for reliable adjustment of the applicator mechanism to maintain a relatively uniform and reliable application of resistance to relative sway of the trailer relative to the towing vehicle. It is desirable that such a device be configured to provide for application of operative forces in a symmetrical pattern relative to the longitudinal center line.